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Thread: Yet another XB12S fuel pump issue.

  1. #1
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    Yet another XB12S fuel pump issue.

    Hi all, I have a 2010 XB12Scg with about 27000 miles on the clock and I am pretty sure my issue is with a fuel pump failure. But before I buy a new fuel pump I wanted to run it by you guys and get your thoughts.

    Here's the story, I was riding on the weekend and my bike just quit without any prior warning leaving me stranded (this included a $420 dollar towing bill, argh!). While waiting for the tow truck I did a quick check of the fuses and found the fuel pump fuse had popped. I tried swapping in the Aux 10 amp fuse and it blew as soon as I turned on the ignition which led me to believe that I had a short to ground somewhere but that is about as far as I got with my roadside diagnoses.

    When I got the bike home I hooked up my Buelltooth and using ECMSpy I got the following codes:

    Historic
    0 Fuel pump pressure fault
    21 AMC Stuck Open x2
    33 Fuel pump short to supply
    Current
    33 Fuel pump short to ground

    I'm not sure why some of the code showed as historic, the last time I had ECMSpy hooked up to the bike (about a month ago) there were no codes at all.

    Seeing this and after going through about a hundred searched posts by guys who have had the same issue you would be led to believe that the problem would be a bad fuel pump and that I should just bite the bullet and replace it but... after doing some further diagnoses and actually un-taping part of the wiring loom to check for damaged wires I pulled the pump (this was made much easier by dropping the swing arm by the way).

    The pump looked fine as they do and I checked for continuity on all wires in the wire harness. They were in perfect shape and there was no evidence on anything shorting or going to ground either in the loom or the harness outside the pump. Then, just out of curiosity I connected the pump out of the bike to a 12 volt source and the pump spun up like it is supposed to!!? So now I'm thinking there may be something else going on and it's not the pump. I reassembled everything, put in a new fuse and it immediately popped just like before.

    Everything I have read says that the pump has failed and that it should be replaced, even the factory electrical diagnostic manual points to the pump as the point of failure. I would be good with that except for the fact that the pump works on its own to a 12 volt source outside the bike. Because the pump works out of the bike and not in makes me wonder if it's something else wrong.

    Am I overthinking this? Do all those additional codes point to something else? I just don't want to buy a new pump only to find out that it was not the issue.

    What do you guys think?

    Any light that you could shed on this would be appreciated.

    Gord

  2. #2
    Senior Member 34nineteen's Avatar
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    Thank you for the detailed diagnosis and putting it all out there. Its soooo much nicer than the "bike doesnt work, checked everything, pls help".

    Anyhow it looks like you are on the correct path. You have established the pump works, and you established there is a short by the popping fuse. I would pull the pump assembly again and check for shorts in the wiring on the tank side of the pump assembly. There have been a few instances of the pump wiring inside the tank being compromised.



    Barrett should be able to speak volumes about this.

  3. #3
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    If you are blowing the fuse then it is possible that the Grey power wire jacket is nicked and shorting to ground INSIDE the frame and that is what is popping your fuse.

    You can see pics of my failure where the power wire arced and melted since the PO had the fusebox modified, so no fuse to pop. You can also see the pump extraction tool I made using an electrical box and some bolts.

    The pump can be extracted without dropping the swingarm, just need to disconnect the shock to get the extra space needed. I can now pull a pump in 60 minutes and that includes setting up the bike using my ladder as an assistant! LOL

    https://www.facebook.com/groups/Buel...8707868569853/
    Last edited by MC Hammered; 07-28-2020 at 06:25 PM.

  4. #4
    Senior Member Barrett's Avatar
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    the 2010 XB fuel pump is unique in several ways from all prior years. won't bore you with the differences.
    Buell/H-D part number is P0130.7AA
    factory parts system shows 2 in existence but the # hasn't been updated in several months. doubt they're still out there.
    the part number likely to be shown NLA during next round of updates. bad news for 2010 XB owners. the 2010-only pump does not have an "onboard" pressure regulator. that regulator is fuel-rail mounted and tied directly via sensor to your ecm. hence, your first 2 listed historical fault codes.
    all years prior healthy pump flirts with 50psi of generated pressure. 2010-only near 60psi. the pressure demands on the motor are exponentially higher than earlier years....likely culprit for your popping fuse.

    there's a few things you can attempt while keeping your fingers crossed. NO guarantee on any of them. as follows:
    1-see pic....2010 only has detachable specific wiring harness. it can chafe internally as well as have corroded harness plug ends causing very high resistance. check same.
    2-the pump motor may appear to operate normally when uninstalled as there's no resistance pressure being applied to the motor. however, when resistance is applied it bogs with resultant popped 10A pump fuse. if the bike were mine and you've already become proficient in R&R on the pump....then remove it and at least replace the motor....strainer...inline high pressure filter and bushings. and of course all the companion seals and O-rings to ensure a leak-proof installation and outlet line fitting.


    p2.jpg

  5. #5
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    Quote Originally Posted by Barrett View Post
    the 2010 XB fuel pump is unique in several ways from all prior years. won't bore you with the differences.
    Buell/H-D part number is P0130.7AA
    factory parts system shows 2 in existence but the # hasn't been updated in several months. doubt they're still out there.
    the part number likely to be shown NLA during next round of updates. bad news for 2010 XB owners. the 2010-only pump does not have an "onboard" pressure regulator. that regulator is fuel-rail mounted and tied directly via sensor to your ecm. hence, your first 2 listed historical fault codes.
    all years prior healthy pump flirts with 50psi of generated pressure. 2010-only near 60psi. the pressure demands on the motor are exponentially higher than earlier years....likely culprit for your popping fuse.

    there's a few things you can attempt while keeping your fingers crossed. NO guarantee on any of them. as follows:
    1-see pic....2010 only has detachable specific wiring harness. it can chafe internally as well as have corroded harness plug ends causing very high resistance. check same.
    2-the pump motor may appear to operate normally when uninstalled as there's no resistance pressure being applied to the motor. however, when resistance is applied it bogs with resultant popped 10A pump fuse. if the bike were mine and you've already become proficient in R&R on the pump....then remove it and at least replace the motor....strainer...inline high pressure filter and bushings. and of course all the companion seals and O-rings to ensure a leak-proof installation and outlet line fitting.


    p2.jpg
    If what you say about the 2010 models uniqueness is fact then I must have a very odd duck on my hands or it has been modified by a PO. I do not have the special harness on my bike and the pump that was installed has the pressure reg as part of the pump. I do think that the pump I have has been replaced before because the tank side wires are Red/Green/Brown and Black and that is not the same as what's listed in the factory wiring diagram.

    Your comment about the pump only blowing fuses while mounted and under load makes sense except that the last fuse I blew was with the pump installed in the tank but no fuel so there should not have been any sort of load on the pump other than it's inherent internal friction.

    I will check and clean all the connectors and apply some di-electric grease to help seal them against the elements.

    I will also carefully inspect all the wiring on the in tank side as well as outside the tank again.

  6. #6
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    Reading fail on my part to not see the "2010" model year of your bike.

    What does the connector plug look like on your pump? Pictures of your pump?

  7. #7
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    Here is the pump that I removed.

    IMG_2317.jpg

    IMG_2316.jpg

    IMG_2318.jpg

  8. #8
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    Looks like the updated version in my 2006 xb9 as yours has the woven sheath to protect the wires from abrasion and the Deutch connector plug.

    Examine the wiring for any damage and shorts to ground. The pump is pretty basic so if it checks out OK then the short is happening on the bike side then.

  9. #9
    Senior Member Barrett's Avatar
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    Gord: below is 2010-only pump. again...the OEM part # is P0130.7AA
    you'll be able to tell from my pics if yours is modded or not. another 2010-only pump clue is that what appears to be reg. has a large metal finger-style clip holding it in place.

    do as you please but considering the fact that this part # appears to be gone now, i would work with what you have...do a full rebuild...carefully check all wiring again including the main wiring feed to the pump harness itself.....and hope that solves your problem.

    2010 xb pump 1.jpg
    2010 xb pump.jpg

  10. #10
    Senior Member Cooter's Avatar
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    Super good info. Get this man a gold star



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